Drafting machine



July 13, 1943. c. H. LITTLE Filed Jan. 2, 1941 2' \TTORNEYj July 13, 1943. c. H. 2,324,457

I DRAFTING MACHINE Filed Jan. 2, 1941 2 Sheets-Sheet 2 INVENTOR. Omezasflfmeyl/rrz- BY ATT( )RNEY5 Patented July 13, 1943 UNITED STATES OFFICE 2,354,457 a I DRAFTING MACHINE Charles Henry Little, Cleveland Heights, Ohio, assignor of one-tenth to Charles Hubbard Little, Cleveland Heights, Ohio Application January 2, 1941, Serial No. 372,796

Claims.

' The present .invention relates to drafting machines and more particularly to drafting machines having a parallel motion mechanism or arm of the wheel and band type. i

The principal object of the present invention is the provision of a novel and improved drafting machine having a parallel motion mechanism-or arm of the wheel and band type wherein the sections or parallelograms of the parallel 'motion mechanism or arm are connected todetails of construction and combinations and arrangements of parts and further objects-and advantages thereof will be apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiment thereof described with reference to the accompanying drawings forming a partof the specification and in which:

Fig. l is a plan view of the drafting machine embodying the present invention; Fig. 2 is an enlarged plan view, with parts broken away, of the elbow. portionof the parallel motion mechanism or arm of the drafting machine shown in Fig. 1;

Flg.'3 is a section with portions in elevation on the line 33 of Fig. 2; and

Fig. 4 is a view similar to Fig. 2 .but showing a modified construction.

The drafting machine shown herein is similar to that shown in a copending application of myself and Charles Hubbard Little, Serial No. 181,790,, now Patent No. 2,228,140 issued January '7, 1941, except for the manner in which the anchor and protractor sections or parallelograms are connected together and for the omission of the counterpoise mechanismuffor the protractor parallelogram. In view of the similarity of the machine disclosed herein to the machine disclosed in the above-mentioned application, only those parts of the present machine are herein illustrated and described which are necessary to a complete understanding of the present invention. For a complete description of the machine generally, reference ismade to said application- Serial No. 181,790.

Referring to the drawings the drafting machine shown therein comprises a parallel motion mechanism or arm of the wheel and band type including angularlymovable sections or parallelograms A and 13 connected together in a manner hereinafter specifically. described. The upper end of the section or parallelogram A shown in'the vertical position, commonly referred to as the anchor section or parallelogram, is operatively connected to the drafting board, designated generally by the reference character C, tziirough the medium of an anchor D which, in the present instance, houses a counterpoise mechanism for the anchor section or parallelogram. The free endof the section or parallelogram B shown in the horizontal position, com

monly referred to as the protractor section or parallelogram, carries a protractor head including a ruler assembly and is designated generally by the reference character E. Each section or parallelogram of the parallel motion mechanism or arm comprises a pair of wheels of equal di: ameter encircled by a flexible band and heldin spaced relation by a strut or frame. Ordinarily,

the two sections or paral-l-elograms are fixedly connected together at the elbow of the parallel mechanism or arm. 1 i

As distinguished from the prior art practice, the present invention contemplates a'fiexible con nection between the parallelograms at theelbow or elbows of the parallel motion arm, which connection permits the drafting head to be raised from the drawing surface without injury to the machine. As shown the wheel l0 located at the elbow end of the anchor parallelogram A, which wheel is encircled by the band H, is connected to a nut or member 92 by a threaded shank I3 formed integral with the wheel. manner the wheel M located at the elbow end of the protractor parallelogram B, which wheel is encircled by the band 15, is connected to a nut or member it similar to the nut i2. The two nuts or members i2 and I6 are adjacent to each other and are connected together by'means which prevents relative rotation therebetween about an axis at right angles to the drawing surface while permitting tween about an axis parallel with the drawing surface. 7 a

Two constructions embodying the present invention are shown in the drawings, the first in Figs. 1 to 3, inclusive, and the second in Fig. 4. As shown in Figs. 1 to 3, inclusive, the nuts or members it and I6 of the anchor and protractor parallelograms, respectively, are connected together by two flexible members in the form of In a similar relative movement therebe-' From the foregoing description, it will be apparent that upon the protractor head E being raised from the drafting surface, the resilient plates I1 and I8 will allow the members 12 and l6 and in turn the wheels l and [4 to separate slightly, as shown in dot-dash lines in Fig. 3. The two parallelograms or sections will pivot relative to each other about an axis parallel to the drawing surface an amount depending upon the material of the plates l1 and 18, the form thereof, and the distance of the rivets l9 from the center of the wheels, etc. The construction is preferably such that the protractor head can be raised a considerable distance from the drawing surface without subjecting the struts or frames to bending stresses which might prove injurious to them.

The construction shown in Fig. 4 is similar to that shown in Figs. 1 to 3, inclusive, except that as shown in Fig. 4 the plates IT and I 8 which correspond to the plates l1 and IS in Figs. 1 to 3, inclusive, are hinged together, in which event it is not necessary that the plates themselves be resilient nor is it necessary for the pivot point to be at one side of the center of the Wheels. As shown the under member l8 has a knuckle box 29 formed integral therewith which fits betweentw knuckles 2| and 22 formed integral with the upper member ll. The knuckle box 26 is rotatably connected to the knuckles 2| and 22 by pivots 23 and 24 respectively, the former of which is in the form of a thumb screw provided with a jamb nut 25 adapted to hold the same in any position to which the screw is adjusted. The pivot 24 is fixedly secured in the knuckle 22. The construction shown in Fig. 4 operates in a manner similar to that shown in Figs. 1 to 3. Both constructions allow the sections or parallelograms of the parallel motion scribed in considerable detail, it will be apparent that the invention is not limited to these constructions and it is my intention to cover hereby all adaptations, modifications, and uses thereof which come within the practice of those skilled in the art to which the invention relates.

Having thus described my invention, what I claimis: I

1. In a drafting-machine of the wheel and band type, the combination of:. a parallel motion mechanism or arm comprising a plurality of.

sections or .parallelograms normally lying in parallel planes anchor means'for connecting one end of said parallel motionarm to a drafting board or the like; each of said sections comprising a pair of wheels, a flexible band encircling said wheels and engaging thev same for maintaining them in definite angular relationship with respect to each other, and a strut operatively connected tosaid wheels for holding the 7 same in spaced relation; and flexible means for operatively connecting together the adjacent wheels of adjoining sections of the parallel motion arm for movementrelativeto each other about a line generally normal to" alinle connect ing the centersof the wheels of the'jsection remote from said anchor means and generally parallel to the plane of said section'whereby;

relative movement may be effected between the sections as units.' 1 V 2. In a drafting machine of the. wheel and band type, thecombination of: a parallel motion mechanism or arm comprising a plurality'of sectionsor'parallelograms normally lying in parallel planes; anchor means for connecting one end of said paralel' motion arm to a drafting board or the-like; each-of said sections comprising a pair of wheels, a flexibleflband encircling said wheels and engaging the'sa'me for maintaining them in definite angular relationship with respect toeach other, andfa strut operatively conarm to pivot or rotate relative to each other at the elbow about an axis'generally parallel to the planes of the p arallelo'grams while preventing any relative rotation between the wheels located at the elbow about an axis perpendicular to the plane of the parallelogram.

From the foregoing description of the preferred embodiments of the invention, it will be apparent that the objects of the invention heretofore enumerated have been accomplished and that applicant has provided a novel and improved drafting machine comprising a parallel motion mechanism of the wheel and band type, the protractor head of which will always lie flat on the drawing surface and can be raised from the drawing surface without injury to the device.

While the invention has been herein illustrated grams supplements the flexibility of. the struts or frames. 7 While the preferred embodiments of the invention have been herein illustrated and denected tosaid wheels for holdingthe same in spaced relation; andme'ans for operatively connecting together the-adjacent wheels of adjoin ing-sections o f"the parallel motion arm for movement relative to each other about an'axis generally normal toa line connecting the centers of the wheels of thje section remote from said anchormeans and generally parallel to the plane of said section wherebythe sections may be movedas units'relativetoeachotherl I,

3. In a drafting =machine,of the :wheel and band type, the combination of: aparallel motion mechanism or'arm-comprising a. plurality ofsections or parallelograms normally lying in parala lel planes; each of said sections comprising a 7 pair of wheels, 9. flexible band encircling said wheels and "engaging the same for maintaining them in definite angula relationship with'respect'to each other, and a strut operatively connected to said wheels for holding the same in spacedrelation; and means for operatively connecting adjoining ends of adjacent: sections of the parallel motion armfor movement as units relativeto each other about an axis generally parallel to the planesthereof; said meanscomprising members respectively connected ,to adjoining wheels of adjacent sections; and means for connectingsaid me" berstogether to one side of the centers of said-wheel's. 4.111 a drafting machine of the wheel and band type, the'combin'ation of g a parallel motion mechanism or' arm comprising a plurality of sections or parallelograms normally lying in V parallel planes; each of said sections'comprising a pair of wheels, a flexible band encircling said wheels and engaging the same for maintaining them in definite angular relationship with respect to each other, and a strut operatively connected to said wheels for holding the same in spaced relation; and means for operatively connecting adjoining ends of adjacent sections of the parallel motion arm for movement as units relative to each other about an axis generally parallel to the planes thereof; said means comprising flexible plates respectively connected to adjoining wheels of adjacent sections, and means for connecting said plates together to one side of the center of said wheels.

5. In a drafting machine of the wheel and band type, the combination of: a parallel motion mechanism or arm comprising a plurality of sections or parallelograms normally lying in parallel planes; each of said sections comprising a pair of wheels, a flexible band encircling sa-id Wheels and engaging the same for maintaining them in definite angular relationship with respect to each other, and a strut operatively connected to said wheels for holding the same in spaced relation; and means for operatively connecting adjoining ends of adjacent sections of the parallel motion arm for movement as units relative to each other about an axis generally parallel to the planes thereof; said means comprising members respectively connected to adjoining wheels of adjacent sections, and pivot means located to one side of the centers of said wheels for connecting said members together.

CHARLES HENRY LITTLE. 

